3 September 1941:
Requisitioned by the IJN as a transport (Ippan Choyosen). [1]

5 September 1941:
Starts conversion to her military role in O.S.K. shipyard.

20 September 1941:
Registered in the IJN under internal order No. 1093 and attached to the Sasebo Naval District as an auxiliary transport, (Ko) category. Her home port is Sasebo. Captain Matsubara Hiromi (39) (former CO of MANJU MARU) is posted Commanding Officer. [2]

6 February 1942: The Invasion of Macassar, Celebes:
The Macassar invasion convoy consists of IJN transports KINAI, NANKAI, HOKUROKU, MATSUE, MONTEVIDEO and YAMASHIMO MARUs. The transports are accompanied by auxiliary oiler SAN CLEMENTE MARU acting as a replenishment vessel.
The convoy is organized in two echelons:

9 February 1942:
Macassar Strait. During the landing of the Sasebo Combined SNLF invasion force, DesDiv 15's NATSUSHIO is torpedoed and sunk by Lt (later Rear Admiral) James C. Dempsey (USNA ’31)'s old submarine USS S-37. NATSUSHIO is only loss suffered by the IJN in the action.

23 May 1942:
Assigned to the Combined Fleet's Second Fleet under secret Navy instruction No. 554 to transport the 14th Naval Construction Unit for the campaign's third phase effective 5 Jun '42.

24 May 1942:
Departs Dairen for Osaka.

27 May 1942:
Arrives at Osaka.

31 May 1942:
Departs Osaka and arrives at Sasebo at an unknown date.

E June 1942:
Due to IJN’s defeat at Midway, the campaign third phase is revised. KINAI MARU is assigned to transport the 14th Naval Construction Unit to the Solomon Islands area.

10 June 1942:
Departs Sasebo for Truk, Carolines.

18 June 1942:
Arrives at Truk.

26 June 1942:
Departs Truk for Lae, New Guinea in convoy with auxiliary transport KENYO MARU, carrying elements of Sasebo 5th Special Landing Naval Force (SNLF). KENYO MARU is later detached for Rabaul, New Britain.

30 June 1942:
Arrives at Lae.

1 July 1942:
Departs Lae for Truk.

3 July 1942:
Arrives at Truk.

12 July 1942:
Departs Rabaul.

13 July 1942:
Arrives at Basabua. Later returns to Rabaul.

6 August 1942:
Departs Rabaul, New Britain for Buna, New Guinea in a convoy also consisting of KENYO and NANKAI MARUs escorted by light cruiser TATSUTA, destroyers YUZUKI and UZUKI and subchasers CH-30 and CH-23 carrying 3,000 men of the 14th and 15th Naval Construction Units, their construction equipment, vehicles, and some army supplies.

7 August 1942:
Following American landings at Guadalcanal and Tulagi, the convoy is recalled by Vice Adm. Gunichi Mikawa (38), commander of the newly established 8th Fleet, when it is only part way to its destination.

9 August 1942:
Arrives back at Rabaul.

12 August 1942:
Departs Rabaul still in same convoy.

13 August 1942:
Arrives at Basabua. Troops disembark.

14 August 1942:
Departs Basabua for Rabaul.

15 August 1942:
Arrives back at Rabaul.

24 August 1942: Operation“RE” Rabbi (Rabi), the Occupation of Milne Bay, Papua, New Guinea:
Departs Rabaul for Rabi in convoy also consisting of NANKAI MARU carrying about 850 men of Cdr Hayashi Masajiro's No. 5 Kure Special Naval Landing Force (SNLF) and a company of the No. 5 SLNF led by Lt Fujikawa, the 10th Naval Construction Party and 2nd Air Advance Party totaling about 360 engineers and non-combat personnel. Rear Admiral Matsuyama Mitsaharu's (40)(former CO of TAKAO) escort consists of CruDiv 18’s TENRYU and TATSUTA and DesDiv 17’s TANIKAZE, URAKAZE and HAMAKAZE and subchasers CH-22 and CH-24.

25 August 1942:
Near Kitava Island, Trobriand Islands. In the afternoon, the convoy is spotted by an RAAF Lockheed "Hudson" bomber. Soon thereafter, 12 RAAF Curtiss P-40 "Kittyhawk" fighters and a Hudson bomber strafe the convoy and attempt to bomb the transports with 250-lb bombs near Rabi Island. Only limited damage is sustained and no ships are sunk.

At 2330, the convoy arrives at Milne Bay. Due to dense fog, landings take place considerably further E of Rabi, between Wahahuba and Ahioma. This gives the Australian garrison time to prepare their defense, and means their P-40s are unhindered in their operations.

26 August 1942:
In the morning, P-40s “Kittyhawks” escort a strike of B-17s “Flying Fortresses” that bombs the invasion force. NANKAI MARU and URAKAZE are damaged. This airstrike forces the convoy to retreat before unloading is completed. Only about 1,150 of the Japanese troops and two Type 95 Ha-Go tanks get ashore. The convoy departs Milne Bay for Rabaul.

10 May 1943:
About 243 nms E of Saipan. At dawn, Bass attacks again the convoy tracked since the day before. At 0400, USS PLUNGER torpedoes and damages KINAI MARU leaving her dead in the water. At 0705, TATSUTAKE MARU is ordered to take off about 400 passengers. At 0748, USS PLUNGER torpedoes TATSUTAKE MARU while she is taking off passengers from KINAI MARU. TATSUTAKE MARU dodges two torpedoes but the third one hits her No. 4 hold and causes a vast explosion. Many of the evacuees are KIA. TATSUTAKE MARU sinks by the stern at 14-33N, 149-23E. Four crewmen are KIA.

At 1253, USS PLUNGER again torpedoes and damages KINAI MARU. In addition, torpedo boat HIYODORI is damaged in collision with TATSUTAKE and KINAI MARUs, during the rescue of survivors.

11 May 1943: In the morning, USS PLUNGER finds KINAI MARU still afloat. LtCdr Bass surfaces and finishes her off with gunfire. She sinks at 0827 in position 14-33N, 149-23E. Only one crewman is KIA. Later that day, HIYODORI arrives at Saipan carrying survivors of KINAI and TATSUTAKE MARUs.

15 July 1943:
Removed from the Navy List under internal order No. 1455.

Authors Notes: [1] See Zatsuyosen home page for full explanation. [2]
There were two categories of Zatsuyosen. (Ko) category with an IJN Captain as supervisor aboard and (Otsu) category without.

Thanks go to Gengoro S. Toda of Japan, Matthew Jones of Mississippi, USA and to Erich Muehlthaler of Germany.